Thoracic and lumbar spine
Lecture Details Tony Buzzard; Week 8 MED1022; Anatomy Lecture Content Support (upper body and upright), transfer loads (between limbs and trunk e.g. walking), movement (to explore environment/run), protection (of spinal cord) Strong but flexible rod made of bone and fibrocartilage (IVD) with supporting ligaments and muscles 7 Cervical (Cx) Lordosis (anterior) (2 degree curvature) (secondary); 12 Thoracic (Tx) Kyphosis (posterior) (1 degree) (secondary); 5 Lumbar (Lx) Lordosis (2 degree) (primary); 5 Sacral (Sx) Kyphosis (1 degree) (primary); 4 Coccygeal (Co) Nerves escape through intervertebral foraminae. Anterior is body, posteriorally is vertebral arch with pedicles and laminae (flat bit). Transverse processes are lateral, spinous processes are posterior, articular processes are postero-superior and inferior, facets articulate with vertebrae above and below. Cervical vertebrae (2-6) have a small body, triangular vertebral foramen, bifid spinous process, relatively large IV discs, transverse foraminae next to body (C1 too) C1 is Atlas, lacks a body or spinous processes, has anterior and posterior arches, articulates with occiput above with elongated condyles, ‘yes’ (0/C1). C2 is Axis, dens (odontoid process) and facet for anterior arch of atlas, articulates with C3 below by flattened horizontal condyles, ‘no’ joint between C1 and 2 Vertebra prominens on C7, has longest spinous processes Thoracic has heart shaped body, circular vertebral canal, have facets on them for articulation of the ribs, long SP’s and TP’s. Lumbar vertebrae, kidney shaped body, thick discs intervene, stout TP and SP. Sacral and coccygeal vertebrae, have base (superior) and apex (inferior), median and lateral sacral crests, sacral canal, sacral foraminae, sacral hiatus, lumbosacral facets (45 degrees) to help L5 from sliding into pelvis due to angle on Co Anterior intervertebral discs (anulus fibrosus surrounds fluid nucleus pulposus inside). Posterior intervertebral (PIV/Facet joints), plane synovial joints, ‘guide’ spine movements Spondylolysis is ‘scotty dog’ malformation. Spondylolisthesis is scotty dog with a break. Lumbar discs keep vertebral bodies together (anulus) and keep them apart (nucleus) as well as bear and distribute loads (especially compressive loads). Anulus fibrosis laminae resist rotation (half in each direction), are thinnest posteriorly, nucleus pulposus is fluid, located posteriorly, decreased water content with age. Problems cause herniation. IVD most susceptible in flexion and rotation, tears can be microscopic (glaucoma) or macroscopic (rupture), 5% of pts with low back pain, center of disc is avascular Nerve supply is sinuvertebral (recurrent meningeal) nerve to outer 1/3 anulus PIV (facet) joints plane synovial joints with accessory ligaments, axis of motion is in the nucleus of the disc, joint movements are guided by the facet plain (NS: dorsal rami of spinal nerves, segmentally), stress fracture of L5 between articular processes is common (spondylolysis/spondylolisthesis) PIV orientation (cervical is oblique, 45) (thoracic coronal) (lumbar sagittal) (L5 S1 45) Movements of spine: flex/ext, lateral flexion, rotation; Ligaments of vertebral column: anulus fibrosus, anterior longitudinal, posterior longitudinal, interspinous, supraspinous, intertransverse, ligamentum flavum, capsular ligaments Deep muscles- oblique (transversospinalis), semispinalis (spans 5, biggest cervically), multifidus (sacral to C2 (3), biggest at lumbosacral), rotatores (thoracic biggest, spans 1). Short group interspinales, intertransversii. Long group (erector spinae), spinalis, longissimus (straightens), iliocostalis Bounded posteriorally by laminae and ligamenta flava, contains spinal cord, cauda equina and coverings. Damage to disc or PIV, will most likely affect spinal nerve that leaves below that level, by damaging the roots Readings